1) Field of the Invention
The invention herein relates to improved diving fins.
2) Description of the Prior Art
The typical structure and operational details of a conventional pair of diving fins are shown in FIG. 1, wherein the longitudinal fin surface 10 of the said fins 1 is comprised of a single web section 102 disposed between longitudinal fluke 101 along two sides. When the diver executes the posterior extension and anterior bending of both legs (conventionally consisting of an alternating upward and downward fluttering action), the two said longitudinal flukes 101 directly support the web section 102 during the aquatic kicking sequence and enables the objective of diver mobility. Undeniably, the single web section 102 of the conventional fins that enables aquatic kicking propulsion possesses practical value and provides functional performance and, furthermore, is currently in widespread use among a majority of divers. However, the inventor of the invention herein discovered several shortcomings that were observed over a period of long-term utilization, each of which can be feasibly improved.
1. To reinforce the web section 102 during aquatic kicking, specifically against contortion due to water drag that results in an incapability to generate thrust, the two longitudinal flukes 101 supporting the web section 102 must be of a relatively hard composition such that when the diver articulates both legs into posterior extension for aquatic kicking and the greater active extent of the fin surface 10 is an inclined disposition, the fin surface 10 and the two longitudinal flukes 101 with which it is formed as a single structural entity and, furthermore, the rigidly configured longitudinal web section 102 must also be in an inclined disposition such that water is kicked at an oblique angle. However, as is well-known by all, the angle at which the said web section 102 generates maximum aquatic kicking efficiency is one that is perpendicular to the traveling direction of the diver. Given the oblique angle of aquatic kicking attack of the said web section 102, the reactive force (i.e., thrust) generated is not proportional to the aquatic kicking power delivered by the diver and results in less than optimal aquatic kicking efficiency.
2. As per the said shortcoming, since the fin surface 10 is in an inclined disposition, the said web surface 102 is accordingly at an oblique angle during aquatic kicking and consequently cannot provide a reactive force (thrust) that is proportional to the aquatic kicking power applied, therefore, to maintain underwater traveling speed, the diver must increase the rate of aquatic kicking, which obviously results in the drawbacks of a greater dissipation of physical strength and an easier onset of fatigue.
3. Since the said planar longitudinal web section 102 and the relatively hard longitudinal fluke 101 are formed as a single structural entity that is rigidly configured, when the diver articulates both legs forward and upward preparatory to aquatic kicking by anterior bending, the forward and upward flexing of the planar web section 102 encounters relatively high fluid drag and, as such, the obvious shortcomings affecting diver articulation are the need use more strength and an inability to effectively increase speed.
4. Since the said two longitudinal flukes 101 are relatively hard constructs, they are capable of supporting the single, large surface area of the web section 102 during the articulation of both legs during aquatic kicking. However, the relatively hard composition of the said longitudinal fluke 101 obviously affects the degree, of pliability of the fin surface 10, which in turn influences the degree of agility and control, resulting in stiffness and lack of smoothness.
In view of the foregoing shortcomings, the inventor of this invention suggested improved diving fins structure as disclosed in the U.S. Pat. No. 6,520,816, in which a first channel A1 is formed transversally across the approximate center portion of a longitudinal web section 102, and a longitudinal fluke 101 along the two sides each with one end proximate a boot section 11 and the other end coupled to a second channel A2 and a third channel A3 which are connected to the first channel A1, so that the web section 102 can be isolated from a fixed first web surface 1021 and a flexile second web surface 1022.
The flexibility and swinging motion of the second web surface 1022 allows the second web surface 1022 to automatically deviate forward during flutter kick execution and then be coordinated into a nearly perpendicular state by the first web surface 1021 to achieve a larger surface area of force application. The force produced by the diver's flutter kicking not only maximizes a reactive force (i.e., thrust) of the aquatic kicking efficiency and increases diver speed, but also lower the kick rate of the diver directly, thereby conserving physical strength and delaying the onset of fatigue.
In other words, the foregoing diving fins structure according to the U.S. patent previously granted to the present inventor can overcome the shortcomings of the conventional diving fins, and divers can optimize the kicking efficiency while conserving physical strength.
Further to conserve physical strength and increasing kicking efficiency for divers of all ages when using the diving fins, the inventor of this invention conducted researches to improve the structure as disclosed in the U.S. Pat. No. 6,520,816, and finally invented this invention.